#include<iostream>
using namespace std;

int main() {
    int n;
    cin >> n;
    if(n%4 == 0) {
        if(n%100 != 0) {
            cout << 29 << endl;
        } else {
            if(n%400 == 0) {
                cout << 29 << endl;
            } else {
                cout << 28 << endl;
            }
        }
    } else {
        cout << 28 << endl;
    }
    return 0;
}